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Discussion Starter · #1 · (Edited)
At BWR we’ve been frustrated with the Lotus transmission since 2006. As we add power and grip the C64 transmissions break. It is pretty robust given that it was designed for far less power than the forced induction cars we are running around with today. However we’ve broken over 10 transmissions in our XP car over the years and many others on track. We do a lot of transmission service work for the lotus community.

There are several issues with this box:

For Track Cars:
1. 1st and 2nd are too short, especially for a supercharged or turbo car.

2. The spacing is pretty wide causing RPM drops that make the car fall off the Big Cam

3. The wide spacing also forces the car out of the power band in higher gears as the aero load increases.

4. 3rd and 4th gears are prone to failure in road raced cars.

For AutoX Cars:
1. 1st and 2nd are too short at 43mph and 67mph for a boosted car.(Assumes stock tire height)

2. Ring and Pinions are known to fail in Pro Solo events at the drag start.

Other Options:
There some other gear sets, but we don’t believe they address these issues very well. Additionally, there is the Quaife sequential and H-pattern Dog Box. They have their issues too. We’ve re-designed an input shaft to fix the weak design from Quaife having broken 2. They are also dog-engagement, not sychro, so streetability is poor.

The e153 Transmission is an option, but it is only 5 speed, requires significant changes in the engine bay such as shifting the engine 2” to the right, and the gear spacing is huge. Lastly, it weighs 30lbs more than the C64.

Given that the C64-based Quaife sequential(with fixed input shaft) has been holding up well to track(Phil’s TT1 car & many others) and Extreme autox duty(my XP car), we believe with better design, heat treatment, and metallurgy we can build a better C64 to meet the needs of today’s forced induction lotus crowd.

I worked over this many times looking for ways to get all the “happy buttons” for all the different use cases. Once I had it narrowed down I got a lot of great input from Phil at BOE on the track-day side.

Our goals were to fix the issues above and add the following features:

1. Make 1st and 2nd tall enough to be usable. 2nd needs to be about 76mph for the AutoX guys.

2. Reduce the spacing between 2-5th to stay in the power band on the track, reduce synchro wear, and keep the engine on boil with increasing aero load.

3. Make 3rd and 4th wider for more strength.

4. Provide a stronger ring & pinion option for drag, pro-solo, or aggressive curb hopping.

5. Use existing synchros and 5th & 6th gear keep costs down (these gears don’t break) and pour the savings into superior quality materials, design, and heat treatment.

6. Keep the gears semi-helical for streetability.

7. Work with an experienced race gear supplier with success in drag and road racing.

Together, we went through a lot of different versions and have finally nailed down a winner.

It looks like this:
- Stock Trans with Stock tires at 8500rpm has 1st going to 43mph and 2nd to 67mph.

- BWR Gears, stock tires, stock Final Drive: 1st at 59mph and 2nd at 81mph.

- BWR Gears, stock tires with new Final drive: 1st at 56mph and 2nd at 76mph.

RPM drops stock vs BWR:
Stock BWR
1-2 2996 2283
2-3 2359 2140
3-4 1808 1447
4-5 1822 1071
5-6 937 937

There are some other interesting options here:

- 59mph in 1st will help hook up all the power and make stoplight battles better.

- Running 15” wheels and 23” tall Hoosiers in the back yields a 148mph top speed and really close ratio NA track attack option.

- Using the Celica taller 6th gear with stock tires means that 5th tops out at 151mph with stock Final drive or 141 with BWR FD, but still has a cruise gear taller than the lotus 6th for the drive home so you don’t buzz your brains out!

- FI autox guys have a useable 1st and the 76mph 2nd with 275/35R17 Hoosiers!

This is still a few months out. It won’t be the cheapest option, but we think it will be the lightest/best option.

:coolnana:
 

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You have me drooling and cursing at you in my head all at the same time. Dang it Fred!!! :D so excited to see what you release these at. :D Are you going to do a parts only option or as a full unit with core charge?
 

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It only took a decade for someone to come up with [what sounds like] a complete solution :D

Very interested to see the updates!
 

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Discussion Starter · #4 ·
You have me drooling and cursing at you in my head all at the same time. Dang it Fred!!! :D so excited to see what you release these at. :D Are you going to do a parts only option or as a full unit with core charge?
I am not sure yet, but I am to do it ala carte. Some folks don't want or need the R&P. Some might want the Celica 6th gear.

Tearing these things down and setting them up right is non-trivial. We'll offer a service as well for folks to send the box to us.
 

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Hi Fred, you said "The e153 Transmission is an option, but it is only 5 speed, requires significant changes in the engine bay such as shifting the engine 2” to the right, and the gear spacing is huge. Lastly, it weighs 30lbs more than the C64."
I have had the E153 in fo a few years now with no problems. They are big and heavy but the only difference in the position of the engine is the thickness of the adapter plate, a bit over 1/2". Just like the Evora and Exige S V6. The ratios are too wide but dropping in the 3&4 from an E53 box gets a much better setup leaving a high 5th for highway cruising. Also they have a cooler and oil pump built in and are hugely strong.
http://www.lotustalk.com/forums/f3/better-e153-gearbox-181698/
 

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Can't wait. This is what I have been looking for. Thank you for putting this together. Looks like a great winter project.
 

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At BWR we’ve been frustrated with the Lotus transmission since 2006. As we add power and grip the C64 transmissions break. It is pretty robust given that it was designed for far less power than the forced induction.
What price range will this upgrade be? Have you tried adding a oil cooler to see if the gearbox will last longer?
 

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Discussion Starter · #8 ·
What price range will this upgrade be? Have you tried adding a oil cooler to see if the gearbox will last longer?
We'll see on price once we get the protos finished. Temperature is not the problem. The breakages have been material/design failures. Not so say that adding a cooler wouldn't be a good idea for an endurance racer, just not what has been the issue thus far.
 

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:up::up: Fred

One question, however. Now that you are making 1st and 2nd into usable gears for us road course junkies, shouldn't you make them wider for durability? First gear drive gear is likely next up on the list of failure points once we start using it more often.

Bob L
 

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Discussion Starter · #10 ·
Bob, Good idea! Already in the plan. Firstly, with the taller ratios we will be making 1st and 2nd Drive(That are on the input shaft) Bigger Diameter and wider. The smaller gear always breaks first. Additionally, the Helix angle will be less for more strength and, of course, better metallurgy and heat treat. You know an autocrosser like me wouldn't forget 1st and 2nd! :D

:up::up: Fred

One question, however. Now that you are making 1st and 2nd into usable gears for us road course junkies, shouldn't you make them wider for durability? First gear drive gear is likely next up on the list of failure points once we start using it more often.

Bob L
 

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i've repaired/modified plenty of these Toyota boxes. happy to offer input, but sounds like you are heading right way.

we been breaking gears in these since they were first used in race celicas in 2000. gears made locally have 100% solved that

FYI, I've been very unhappy with the jubu helical gears. poor dimensional control.

I've done lots of E153 repairs/mods and wrote a substantial tech article on them. they are NOT the box for any 4 cyl race Lotus, no matter what some vendors might tell you. The super-rare close ratio E box was a lot better ratio wise, but stock syncros were still too slow for a race box . we have one in a V6 exige we are building, but with the supercharged V6, lightning gear changes are not a priority. it will never break!
 

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Ok I'm gonna weigh in. :)

I still think that my ideal transmission would be a stock C64 with the C66 final drive (3.941). That gives a better spread for the big forced induction cars.

This would yield these mph's @ 8500 redline in each gear on stock tires:

Stock: 43, 66, 91, 116, 148, 166 (~3000 @ 60mph in 6th)
C66 final: 49, 76, 105, 133, 170, 191 (~2600 @ 60mph in 6th)

This lets you do the following to the gears...

1st: May actually be useful since it's a bit taller
2nd: Reach over 60mph
3rd: Reach over 100mph
4th: Let's you run the quarter mile without shifting into 5th... :drool:
5th: Reach over 150mph in 5th - one should never see redline here :crazyeyes
6th: Lowers rpm on the highway for "economy"

If something like this was made with nuclearized components I'd buy one in a heartbeat.

So... what are the actual gear set ratios of your proposed box?
 

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Worked with Fred real close on this project and I'm excited to see him moving forward with it! Nice to have a partner like Fred/BWR when making these cars better!!! :up:
@darkSol-With factory FD and your taller drag radials, you'll basically hit 60 in first! You'll have plenty of power to pull it off too--- will make for sime nice 0-60 times:)

For smaller road course tires, 1st won't make it to 60 though.

As for the quarter mile, 4th will get you through the traps, so I think you'll be a buyer! :D ---now you just need to find a dragstrip since they're all closed in the area now :(:facepalm

Good stuff:nanner2:

-Phil
 

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Discussion Starter · #16 ·
DS,

Our gear set will be 123 in 4th with new FD and stock sized tires, though in truth, you should be running taller for drag. If you run 25" i.e. 255/40R17 you are right at 125mph. Either is probably good enough for 1/4 mile?

The C66 gearing is that it isn't good for track folks.
- 1st is too short so you are beating up the synchro in 2nd.
- 5th and 6th are too tall. A 170mph 5th can't make use of the power on most tracks. 140mph is really where you want 5th. Make 6th the cruise.
The Celica 6th gear will give you 10mph taller 6th than stock.



Ok I'm gonna weigh in. :)

I still think that my ideal transmission would be a stock C64 with the C66 final drive (3.941). That gives a better spread for the big forced induction cars.

This would yield these mph's @ 8500 redline in each gear on stock tires:

Stock: 43, 66, 91, 116, 148, 166 (~3000 @ 60mph in 6th)
C66 final: 49, 76, 105, 133, 170, 191 (~2600 @ 60mph in 6th)

This lets you do the following to the gears...

1st: May actually be useful since it's a bit taller
2nd: Reach over 60mph
3rd: Reach over 100mph
4th: Let's you run the quarter mile without shifting into 5th... :drool:
5th: Reach over 150mph in 5th - one should never see redline here :crazyeyes
6th: Lowers rpm on the highway for "economy"

If something like this was made with nuclearized components I'd buy one in a heartbeat.

So... what are the actual gear set ratios of your proposed box?
 

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purveyor of lightness
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FZ (If you can call me DS I can call you da FuZz :) )...

If you run 25" i.e. 255/40R17 you are right at 125mph. Either is probably good enough for 1/4 mile?
Nope - back in 2011 I was running EFI with a 9160rpm redline AND 245-45-17 Nitto Drag Radials (with my stock pegleg C64). I managed these speeds at redline:

47, 73, 101, 128, 163, 183 <- and I hit the rev limiter in 4th ninety-six feet after passing the quarter mile timing lights. 11.477 @ 123.59 mph... granny shifting for the synchros:


Now that I'm running stock FastWorks ECU @ 8500 I would be confined to these speeds with the exact same setup:

44, 68, 94, 119, 151, 170 <- MOST definitely have to shift to 5th before finishing.


The C66 gearing is that it isn't good for track folks.
I was just referring to the final drive, not the horrific drive gear ratio selection of the C66.

I really like the C64 ratios - even 6th. Just wish they were loooonger. The MR2 Spyder's C65 final drive (4.312) only stretches it out a bit:

Final Drive, stock 1-6 ratio...
C64: 43, 66, 91, 116, 148, 166
C65: 45, 69, 96, 122, 155, 175 <- I do like 5th gear with 155 though.
C66: 49, 76, 105, 133, 170, 191

Make an option with nuclear 1st-4th stock ratio gears and we'll change out the final drive to the C66. That puppy will last forever.

Now that I'm 100 lbs. lighter and have more boost it's even more important :)

So... once again... what ARE the new ratios? :cool:
 

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Discussion Starter · #18 ·
Dave, with your tall tires, you have headroom in 4th mph-wise for the 1/4. :)

The Ratios aren't disclosed yet because they may change slightly over the prototyping phase. All will be made known in due time.
 

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Dave, with your tall tires, you have headroom in 4th mph-wise for the 1/4. :)

The Ratios aren't disclosed yet because they may change slightly over the prototyping phase. All will be made known in due time.
Ahhh... That's why it's so FuZzy :)

Looking forward to the details!

-D
 
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